A Cross-Layer Scheme for Access Point Selection in Wireless Mesh Networks

In wireless mesh networks (WMNs), a station (STA) often has a group of candidate access points (APs) to be associated with. How to select the most appropriate AP has been an open problem. In IEEE 802.11 standards, the STA simply chooses the one with the strongest RSSI. Since this AP selection strategy can cause severe network load unbalance, many new methods have been proposed. However, these solutions mainly focus on the WLAN environment and are not applicable for WMNs. The unique wireless multi-hop backbone in WMN will introduce higher latency, which must be considered during the AP selection process. In this paper, we propose a cross-layer AP selection scheme based on the information of both link layer and routing layer aiming at reducing the network transmission delay. The problem is formulated as a nonlinear programming problem, and a heuristic search algorithm is given. Experiment results show that the cross-layer scheme can reduce the mean delay of the whole network by about 30% and can benefit real-time applications.